Monolithic gas distribution manifold and various construction techniques and use cases therefor

ABSTRACT

A gas delivery substrate for mounting gas supply components of a gas delivery system for a semiconductor processing apparatus is provided. The substrate may include a plurality of layers having major surfaces thereof bonded together forming a laminate with openings for receiving and mounting first, second, third and fourth gas supply components on an outer major surface. The substrate may include a first gas channel extending across an interior major surface that at least partially overlaps a second gas channel extending across a different interior major surface. The substrate may include a first gas conduit including the first gas channel connecting the first gas supply component to the second gas supply component, and a second gas conduit including the second channel connecting the third gas supply component to the fourth gas supply component. Also disclosed are various techniques for manufacturing gas delivery substrates.

INCORPORATION BY REFERENCE

An Application Data Sheet is filed concurrently with this specificationas part of the present application. Each application that the presentapplication claims benefit of or priority to as identified in theconcurrently filed Application Data Sheet is incorporated by referenceherein in its entirety and for all purposes.

FIELD OF THE INVENTION

The invention relates to gas delivery systems for semiconductorsubstrate processing apparatuses. More particularly, the inventionrelates to a gas delivery substrate for mounting gas supply componentsof a gas delivery system for a semiconductor processing apparatus.

BACKGROUND

Semiconductor substrate processing apparatuses are used for processingsemiconductor substrates by techniques including, but not limited to,plasma etching, physical vapor deposition (PVD), chemical vapordeposition (CVD), plasma enhanced chemical vapor deposition (PECVD),atomic layer deposition (ALD), plasma enhanced atomic layer deposition(PEALD), ion implantation, and resist removal. Semiconductor substrateprocessing apparatuses include gas delivery systems through whichprocess gases are flowed and subsequently delivered into a processingregion of a vacuum chamber of the semiconductor processing apparatus bya gas distribution system such as a showerhead, gas injector, gas ring,or the like. For example, the gas delivery system may be configured tosupply process gas to a gas injector positioned in the semiconductorprocessing chamber above a semiconductor substrate so as to distributeprocess gases over a surface of the semiconductor substrate beingprocessed in the semiconductor processing chamber. Current gas deliverysystems are constructed from many individual components, many of whichhave conduits therein through which process gas flows.

Conventional semiconductor processing systems typically utilize gassticks. The term “gas sticks” refers, for example, to a series of gasdistribution and control components such as a mass flow controller(MFC), one or more pressure transducers and/or regulators, a heater, oneor more filters or purifiers, and shutoff valves. The components used ina given gas stick and their particular arrangement may vary dependingupon their design and application. In a typical semiconductor processingarrangement, over seventeen gas sticks may be connected to thesemiconductor processing chamber via gas supply lines, gas distributioncomponents, and mixing manifolds. These are attached to a base plateforming a complete system known as a “gas panel” or “gas box” whichserves as a mounting surface for the gas sticks and which does not playa role in the gas distribution.

In general, a gas stick includes multiple integrated surface mountcomponents (e.g., valve, filter, etc.) that are connected to other gascontrol components through channels on a substrate assembly or baseplate, upon which the gas control components are mounted. Each componentof the gas stick is typically positioned above a manifold block in alinear arrangement. A plurality of manifold blocks form a modularsubstrate, a layer of manifold blocks that creates the flow path ofgases through the gas stick. The modular aspect of conventional gassticks allow for reconfiguration, much like children's LEGO® block toys.However, each component of a gas stick typically includes highlymachined parts, making each component relatively expensive tomanufacture and replace. Each gas flow component is typicallyconstructed with a mounting block, which in turn is made with multiplemachine operations, making the component expensive.

SUMMARY

Details of one or more implementations of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages will becomeapparent from the description, the drawings, and the claims. Note thatthe relative dimensions of the following figures may not be drawn toscale unless specifically indicated as being scaled drawings.

Disclosed herein is a gas delivery substrate for mounting the gas supplycomponents of a gas delivery system gas box for a semiconductorprocessing apparatus. The substrate may include a plurality of layershaving major surfaces thereof bonded together to form a laminate. Thelaminate may include openings configured to receive and mount at least afirst gas supply component, a second gas supply component, a third gassupply component, and a fourth gas supply component on an outer majorsurface of at least one of the layers. The substrate may also include afirst gas channel extending at least partially across an interior majorsurface of one of the layers and a second gas channel extending at leastpartially across a different interior major surface of one of thelayers. The first gas channel may at least partially overlap the secondgas channel when viewed from a direction perpendicular to the majorsurfaces of the layers. In addition, the substrate may include a firstgas conduit that may include the first gas channel and which may beconfigured to connect the first gas supply component to the second gassupply component, and a second gas conduit including the second channelconfigured to connect the third gas supply component to the forth gassupply component.

Also disclosed herein is a system for a semiconductor manufacturingsystem gas box that includes the gas delivery substrate. The systemincludes gas supply components mounted on at least one major surface ofthe gas delivery substrate. In one implementation, the gas supplycomponents may be mounted on opposing major surfaces of the gas deliverysubstrate. In another implementation, the system may include an on/offgas valve connected to an MFC through a gas conduit within thesubstrate, another on/off gas valve connected to a mixing manifold orchamber through a gas conduit within the substrate, and a mixingmanifold or mixing chamber exit connected to one or more openings of thegas delivery substrate.

Disclosed herein is also a method of producing a gas delivery substrate.The method may include creating a first gas channel extending at leastpartially across an interior major surface of at least one layer of aplurality of layers having major surfaces thereof, creating a second gaschannel extending at least partially across a different interior majorsurface, and creating openings on an outer major surface. At least someof the openings may be mounting holes configured to receive and mount atleast a first gas supply component, a second gas supply component, athird gas supply component, and a fourth gas supply component. Themethod may further include bonding the layers together to form alaminate such that the first gas channel is at least partiallyoverlapping the second gas channel, the first gas channel forms part ofa first gas conduit connecting the first gas supply component to thesecond gas supply component, and the second gas channel forms part of asecond gas conduit connecting the third gas supply component to thefourth gas supply component.

Also disclosed herein is a method of delivering gas through such a gasdelivery substrate when the gases are supplied through the openings ofthe gas delivery substrate. The method may include delivering a firstgas from the first gas supply component to the second gas supplycomponent through the first gas channel, and delivering the first gasfrom the second gas supply component to a mixing chamber within thesubstrate through a third gas channel in the substrate. The method mayfurther include delivering a second gas from the third gas supplycomponent to the fourth gas supply component through the second gaschannel, and delivering the second gas from the fourth gas supplycomponent to the mixing manifold or chamber within the substrate througha fourth gas channel in the substrate. The method may also includemixing the first gas and the second gas in the mixing chamber to createa first gas mixture and delivering the first gas mixture through one ormore gas channels in the substrate and/or one or more outlets on thesubstrate to a semiconductor processing chamber downstream.

In some implementations, a method may be provided that includesobtaining a ceramic substrate having a first side and second sideopposite the first side. The ceramic substrate may include asurface-mount valve interface that is located on the first side; thesurface-mount valve interface may include two or more holes in theceramic substrate. The method may further comprise lapping or polishingat least one surface of the ceramic substrate surrounding the two ormore holes such that the surface roughness of the at least one surfaceis less than or equal to 5 μin Ra.

In some implementations of the method, the method may further includepositioning a crushable metal seal around at least one of the two ormore holes, positioning a surface-mount gas flow component such that theat least one of the two or more holes aligns with a gas flow port on thesurface-mount gas flow component and the crushable metal seal, andclamping the surface-mount gas flow component to the ceramic substrateusing one or more fasteners, thereby compressing the crushable metalseal against the surface or surfaces having the surface roughness thatis less than or equal to 5 μin Ra.

In some such implementations, the crushable metal seal may be a C-seal,a W-seal, or a metal o-ring. In some implementations of the method, theat least one of the two or more holes is counterbored such that thecrushable metal seal is at least partially recessed within thecounterbore of the hole when installed, and the at least one surfacethat is lapped or polished includes the floor of the counterbore. Insome implementations of the method, the at least one surface may includethe entire first side.

In some implementations, an apparatus may be provided that includes aceramic substrate. The ceramic substrate may have a first side andsecond side opposite the first side, and may include a surface-mountvalve interface that is located on the first side. The surface-mountvalve interface may include two or more holes in the ceramic substrate,and the surface or surfaces surrounding the holes may have a surfaceroughness less than or equal to 5 μin Ra.

In some implementations, the apparatus may further include a crushablemetal seal and a surface-mount gas flow component with one or more gasflow ports. The surface-mount gas flow component may be mounted to theceramic substrate such that each gas flow port aligns with one of theholes, the crushable metal seal is interposed between the surface-mountgas flow component and the ceramic substrate, and the crushable metalseal is in contact with one of the surfaces having the surface roughnessless than or equal to 5 μin Ra.

In some such implementations, the crushable metal seal may be a C-seal,a W-seal, or a metal o-ring. In some implementations of the apparatus,the ceramic substrate may further include at least one counterborefeature, and the at least one counterbore feature may correspond inlocation to one of the two or more holes and have a floor thatintersects with the hole. In such implementations, the at least onesurface that is lapped or polished to a surface roughness of less thanor equal to 5 μin Ra may include the floor. In some implementations ofthe apparatus, the at least one surface may include the entire firstside.

In some implementations, a method is provided. The method may includemanufacturing a ceramic substrate having a first side and second sideopposite the first side and including a plurality of surface-mount valveinterfaces located on one or both of the first side and the second side,one or more channels located between the first side and the second side,and a plurality of drop-holes fluidically connecting the one or morechannels with the surface-mount valve interfaces. The method may furtherinclude forming a coating on at least surfaces of the channels withinthe ceramic substrate.

In some implementations of the method, the manufacturing the ceramicsubstrate may include manufacturing a plurality of ceramic layers,laser-cutting the one or more channels into one or more of the layers,bonding the plurality of ceramic layers together, and sintering thebonded layers to form the ceramic substrate.

In some implementations of the method, the coating may have a thicknessgreater than or equal to the smallest nominal particle size of ceramicparticles used to make the ceramic substrate or the maximum surfaceroughness exhibited by the surfaces of the one or more channels.

In some implementations of the method, the method may further includeapplying a glaze to surfaces of the channels, firing the ceramicsubstrate in a kiln or oven to melt the glaze, and cooling the ceramicsubstrate to solidify the molten glaze and form the coating.

In some implementations of the method, the method may further includeinserting the ceramic substrate into a chemical vapor deposition (CVD)chamber and performing one or more CVD operations on the ceramicsubstrate to form the coating.

In some implementations of the method, the method may include masking,prior to performing the one or more CVD operations, portions of thefirst side or the second side to prevent the coating from beingdeposited on the masked portions.

In some implementations of the method, the method may further includeinserting the ceramic substrate into an atomic layer deposition (ALD)chamber and performing a plurality of ALD operations on the ceramicsubstrate to form the coating.

In some implementations, an apparatus may be provided. The apparatus mayinclude a ceramic substrate having a first side and second side oppositethe first side, a plurality of surface-mount valve interfaces located onone or both of the first side and the second side, one or more channelslocated between the first side and the second side, a plurality ofdrop-holes fluidically connecting the one or more channels with thesurface-mount valve interfaces, and a coating on at least surfaces ofthe one or more channels within the ceramic substrate.

In some implementations of the apparatus, the ceramic substrate mayinclude a plurality of ceramic layers that are sintered together, andthe one or more channels may have sidewalls that are laser-cut into oneor more of the layers.

In some implementations of the apparatus, the coating may have athickness greater than or equal to the smallest nominal particle size ofceramic particles used to make the ceramic substrate or the maximumsurface roughness exhibited by the surfaces of the one or more channelssidewalls.

In some implementations of the apparatus, the coating may be asilica-containing glaze. In some other implementations of the apparatus,the coating may be a chemical vapor deposition (CVD) coating. In somesuch implementations of the apparatus, the CVD coating may be apolymeric coating. In some other implementations of the apparatus, thecoating may be a conformal atomic layer deposition (ALD) coating.

These and other implementations are described in further detail withreference to the Figures and the detailed description below.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 illustrates an example implementation of a semiconductorsubstrate processing apparatus in accordance with implementationsdisclosed herein.

FIG. 2 is a schematic of an example gas delivery system in accordancewith implementations disclosed herein.

FIG. 3 illustrates an example of a gas stick.

FIGS. 4-6 illustrate various views of a modular gas stick.

FIGS. 7 through 9 illustrate example implementations of single layers ina gas delivery substrate for mounting gas supply components of a gasdelivery system for a semiconductor processing apparatus, in accordancewith implementations disclosed herein.

FIGS. 10 and 11 illustrate multiple example layers of an example gasdelivery substrate for mounting gas supply components before beingbonded together, in accordance with implementations disclosed herein.

FIG. 12 illustrates multiple layers of an example gas delivery substratefor mounting gas supply components of a gas delivery system after beingstacked together, in accordance with implementations disclosed herein.

FIG. 13 illustrates multiple layers of the example gas deliverysubstrate of FIG. 12 after being stacked together and bonded, inaccordance with implementations disclosed herein.

FIG. 14 depicts a three-dimensional rendering of the fluid flowconduits, e.g., channels and vertical through-holes, located within theexample gas delivery substrate of FIGS. 10-13.

FIG. 15 depicts a plan view of the example gas delivery substrate ofFIG. 12.

FIG. 16 depicts an isometric view of an example gas delivery systemutilizing an example layered substrate.

FIG. 17 depicts an isometric exploded view of the example gas deliverysystem of FIG. 16.

FIG. 18 depicts an exploded section view of a typical C-seal interfacebetween a gas supply component and a metal base.

FIG. 19 depicts a section view of the assembled C-seal interface of FIG.18.

FIG. 20 depicts a flow diagram for a technique for preparing a ceramicsubstrate for interfacing with a gas flow component using a standardcrushable metal seal, such as a metal C-seal.

FIG. 21 depicts a cross-section of an arrangement in which the entiresurface of a ceramic substrate may be polished or lapped to a surfaceroughness of less than or equal to 5 μin R_(a).

FIG. 22 depicts a flow diagram for a technique for preparing a ceramicsubstrate for a semiconductor tool gas distribution system so as to havea reduced likelihood of particulate contamination.

FIGS. 23 through 25 depict simplified cross-sectional views of a ceramicsubstrate and masking components during various stages of a CVD coatingapplication.

FIGS. 4-17 are drawn to-scale within each Figure, although the scale mayvary from Figure to Figure.

DETAILED DESCRIPTION

Disclosed herein is a gas delivery substrate for mounting gas supplycomponents, also referred to herein as gas flow components, of a gasdelivery system for a semiconductor processing apparatus and methods forproducing and using the same. The semiconductor substrate processingapparatus may be used for processing semiconductor substrates bytechniques including, but not limited to, plasma etching, physical vapordeposition (PVD), chemical vapor deposition (CVD), plasma enhancedchemical vapor deposition (PECVD), atomic layer deposition (ALD), plasmaenhanced atomic layer deposition (PEALD), ion implantation, or resistremoval. In the following description, numerous specific details are setforth in order to provide a thorough understanding of the presentimplementations. It will be apparent, however, to one skilled in the artthat the present implementations may be practiced without some or all ofthese specific details. In other instances, well known processoperations have not been described in detail in order not tounnecessarily obscure present implementations disclosed herein.

As integrated circuit devices continue to shrink in both their physicalsize and their operating voltages, their associated manufacturing yieldsbecome more susceptible to contamination. Consequently, fabricatingintegrated circuit devices having smaller physical sizes requires thatthe level of contamination be less than previously considered to beacceptable. In addition, the wafers and processing equipment used insemiconductor processing are becoming more complex and larger in size,in order to produce more dies per wafer. Accordingly, producing andmaintaining the equipment and manufacturing the wafers is becoming moreexpensive.

Gas distribution systems of semiconductor substrate processingapparatuses may utilize gas sticks, each of which may be a series of gasdistribution and control components such as, for example, a mass flowcontroller (MFC), one or more pressure transducers and/or regulators,one or more heaters, one or more filters or purifiers, manifolds, gasflow adaptors, and/or shutoff valves. The components used and theirparticular arrangement in a gas stick may vary depending upon theirdesign and application. The number of gas sticks used in a particulargas distribution system may vary depending on the needs of thesemiconductor process performed. For example, in some semiconductorsubstrate processing arrangements, over seventeen process gases, eachsupplied by a different gas stick, may be supplied to the chamber. Suchgas distribution system components are typically attached to a baseplate, typically called a “gas pallet,” to form the system which iscommonly known as a “gas panel” or “gas box.”

As discussed above, gas delivery system components are traditionallymade from metals such as stainless steel or other metal alloys and thenassembled together, requiring interfaces and seals between theconstituent components, in order to achieve desired conduit paths forprocess gases. However, the constituent components typically includeprecision-machined parts, making each component relatively expensive tomanufacture, maintain, and replace. Each component is typically attachedto a mounting block or base, which, in turn, is also precision-machined,making the component expensive. There may, for example, be threeseparate seal interfaces that require precision machining in a simpleon/off valve—one that joins the valve assembly to its mounting block orbase, one that joins the mounting block or base to a modular substratemodule, and one or two that join the modular substrate module to othermodular substrate modules forming a gas stick. Such interchangeablecomponents require a substantial amount of space, which lengthens thefluidic connections that connect the components with each other. Thus,gas sticks made using the conventional interchangeable componentapproach have multiple potential failure points (in the form of multipleseals), include multiple contamination points (each seal interfacerepresents a contamination point), and introduce gas delivery delays(due to their length).

Corrosion, erosion, and/or corrosion/erosion in environments, such asthose formed in the interior of gas delivery systems may contain oxygen,halogens, carbonyls, reducing agents, etching gases, depositing gases,hydro-fluorocarbon process gas, and/or process gases which may be usedin semiconductor substrate processing such as but not limited Cl₂, HCl,BCl₃, Br₂, HBr, O₂, SO₂, CF₄, CH₂F₂, NF₃, CH₃F, CHF₃, SF₆, CO, COS,SiH₄, and H₂. In addition inert gases, such as but not limited Ar andN₂, may be supplied to said environments.

Accordingly, disclosed herein is a gas delivery substrate for mountinggas supply components for multiple gas feeds of a gas delivery systemfor a semiconductor processing apparatus and methods for producing andusing the same. The substrate may be formed from laminated layers whichare bonded together to create a uniform monolithic structure havinggas-tight channels that may be in fluidic communication with each other.These layers may be made from a variety of materials, including, forexample, stainless steels, glass, or ceramics. In implementations usingmetal layers, the layers may be brazed together or otherwise bondedtogether. In implementations using ceramic layers, the layers may bebonded together before sintering and then sintered into a fused layerstack; the bonding material is typically burned off during the sinteringprocess, resulting in a generally homogenous ceramic part.

The substrate may be configured to receive and mount gas supplycomponents such that the gas supply components are in fluidiccommunication with each other via channels within the substrate. Thelayered structure of the substrate may allow channels or connections tobe created of any size and in any direction in the X/Y planes ofmultiple layers, each of which may be connected to other channels orports in other layers by connections in the Z direction within thesubstrate. For the purposes of this disclosure, the X and Y directionsare defined as being parallel to the major surfaces of each layer, andthe Z direction is defined as being perpendicular to each layer. Thenetworks of channels within the layers may allow for complex, non-linearfluid routing arrangements that are not possible using conventionalmodular substrates. It is to be understood that, as used herein, thephrase “linear fluid routing” refers to fluid routing in which the fluidflow components in a fluid flow path are arranged in a line and thefluidic connections between such fluid flow components in planesparallel to the surfaces on which such fluid flow components mountgenerally travel in one direction or in parallel directions. Incontrast, “non-linear fluid routing” refers to fluid routing in whichthe fluid flow components in a fluid flow path are not all arranged in aline and in which at least one fluidic connection between such fluidflow components follows a path having at least one non-orthogonal anglein it. In certain implementations, non-linear fluid routing may be usedin which at least a portion of the fluidic connection between such fluidflow components follows a curvilinear path, i.e., at least a portion ofthe path is not a line, but a curve, arc, or spline; such furtherexamples of non-linear fluid routing may be referred to as “curvilinearfluid routing.” Existing gas box designs typically feature collectionsof fluid flow components that are arranged to provide fluid flownetworks having linear fluid routing, e.g., 16 gas sticks having linearfluid routing may be arranged to join with line of T-junctions that havea linear fluid routing direction that is at 90° to the linear fluidrouting directions of the gas sticks—at the gas stick level, the flowpaths are all linear in nature.

Due to the flexibility in X, Y, and Z routing that is afforded in thelayered or laminated substrate, non-linear fluid routing may be used,which allows for non-linear fluid flow component layouts. Moreover, dueto the fact that the layered substrate approach allows for channels tocross over one another, it is possible to locate fluid flow componentsfrom a particular gas flow path on either side of another gas flow path,which provides further flexibility in mounting locations.

In this way, gas supply components of a gas delivery system may behoused closer together and various critical connections betweencomponents may be made shorter, which reduces the overall size of thegas delivery system (or allows for a gas delivery system with increasedcapacity to be housed in the same form factor as a smaller capacitytraditionally-designed gas box) and reduces gas flow transit timebetween gas supply components. In addition, gas supply components andtheir connections are often made from high quality materials, such asexpensive metal alloys, e.g., Hastelloy®, glass or ceramics—thisdramatically increases the costs of certain components, e.g., modularsubstrate components—use of a layered substrate, as disclosed herein,may allow for a large number of expensive parts, such as the modularsubstrate pieces, tubing, fittings, etc., to be replaced by one, largerpart. This larger part, while more expensive than any of the piece partsthat it may replace, may nonetheless offer significant savings over allof the piece parts that it may replace. Moreover, by using a layeredsubstrate, the assembly time needed to assemble the various piece partsthat the layered substrate may replace may be eliminated, resulting infurther savings. Use of a layered substrate also allows all of the sealsbetween various piece parts, e.g., between modular substrate pieces, tobe eliminated, which reduces the amount of leak testing that must bedone, thereby further reducing the costs of such systems.

If a ceramic substrate is used, all of the metallic surfaces whichtypically contact process gases, i.e., become chemically wetted, withina typical modular substrate may be eliminated or reduced so as to complywith on wafer, i.e., substrate, purity requirements. The compact designof the layered substrate (as compared with the traditional gas-stickapproach) allows for reduced material costs, a reduction of the numberof possible contamination and failure points, and faster gas deliverypulsing and switching times for a gas delivery system by virtue ofallowing for shorter gas flow paths between certain critical flowcomponents.

FIG. 1 illustrates an implementation of a semiconductor substrateprocessing apparatus 104, e.g., an inductively coupled plasma processingapparatus, which may include a gas delivery system 102 including a gasdelivery substrate for mounting gas supply components, as disclosedherein. As shown in FIG. 1, the inductively coupled plasma processingapparatus may include a vacuum chamber 104, e.g., a plasma etch chamber.The vacuum chamber 104 may include a substrate support (lower electrodeassembly) 106 for supporting a semiconductor substrate 108 in theinterior of the vacuum chamber 104. A dielectric window 110 may form atop wall of the vacuum chamber 104. Process gases may be injected intothe interior of the vacuum chamber 104 through a gas injector 112. Thegas delivery system 102 may supply process gases to the interior of thevacuum chamber 104 through the gas injector 112. Parameters, e.g.,temperature, flow rate, and chemical makeup, of the process gasessupplied to the interior of the vacuum chamber by the gas deliverysystem may be controlled by a control system 114.

Once the process gases are introduced into the interior of vacuumchamber 104, they may be energized into a plasma state by an antenna 116supplying RF energy into the interior of vacuum chamber 104. The antenna116 may be a planar antenna powered by an RF power source 122 and RFimpedance matching circuitry 118 to inductively couple RF energy intothe vacuum chamber 104. However, in an alternate implementation, theantenna 116 may be an external or embedded antenna which is nonplanar.An electromagnetic field generated by the application of RF power to theantenna may energize the process gas in the interior of the vacuumchamber 104 to form high-density plasma, e.g., 109-1012 ions/cm3, abovethe substrate 108. During an etching process, the antenna 116, i.e., anRF coil, may perform a function analogous to that of a primary coil in atransformer, while the plasma generated in the vacuum chamber 104performs a function analogous to that of a secondary coil in thetransformer. The antenna 116 may be electrically connected to the RFimpedance matching circuitry 118 by an electrical connector or lead 120and the RF power source 122 may be electrically connected to the RFimpedance matching circuitry 118 by an electrical connector 124.

FIG. 2 is a schematic view of an example gas delivery system 200 for asemiconductor substrate processing apparatus processing including a gasdelivery substrate for mounting gas supply components, as disclosedherein. A vacuum chamber 210 of a semiconductor substrate processingapparatus may be supplied process gas through a gas supply line 214. Thegas supply line 214 may provide process gases, such as etching and/ordeposition gases, which may be alternatively supplied or pulsed, to agas distribution member such as a showerhead or a gas injector arrangedin the upper portion of the vacuum chamber 210, and downstream of thegas delivery system 200. Additionally, the gas supply line 214 maysupply process gas to a lower portion of the vacuum chamber such as, forexample, to a gas distribution ring surrounding the semiconductorsubstrate support or through gas outlets arranged in the substratesupport (not shown). Processing gas may be supplied to gas line 214 fromgas supplies 216, 218, 220, 230 with the process gases from supplies216, 218, 220, 230 being supplied to MFCs 222, 224, 226, 232respectively. The MFCs 222, 224, 226, 232 supply the process gases to amixing manifold 228 after which the mixed gas is directed to gas flowline 214. Mixing manifold 228 may be within the substrate for mountinggas supply components or external to the substrate. The gas deliverysystem 200 includes a layered substrate for mounting gas supplycomponents, as disclosed herein.

FIG. 3 illustrates a cross section of a prior art gas stick with amodular substrate 322 and the flow of gases through such a gas stick.The gas may flow through a primary shut-off valve 314, out of a purgevalve 316, and into an MFC 318 in the direction of flow path A. The gasmay then flow out of the MFC 318 via an exit port 300 and into themodular substrate 322, through the mixing valve 320, out of an outlet326, and into a mixing manifold or chamber (not shown), as illustratedby flow path D.

Substrate 322 is of a modular design which includes multipleinterchangeable parts which are connected to each other with seals,which each introduce potential failure points in the gas stick assembly.Since substrate 322 is made up of multiple parts, it allows for a LEGO®type construction, which provides flexibility in how each gas stick isassembled. However, this design causes the flow path between gas supplycomponents to become long, which increases fluid flow path lengths andthus transit time of gases, and introduces multiple failure points inthe gas stick, as discussed above. In a conventional semiconductorprocessing gas box, the gas box includes discrete gas sticks, built upon discrete substrates such as the modular substrate 322, that are thenmounted to a common mounting plate—the fluid flow passages in suchconventional gas boxes are provided by the discrete substrates and arenot included in the mounting plate.

FIGS. 4 through 6 show another example of a modular substrate gas stick.In FIG. 6, the individual piece-parts of the modular substrate areclearly shown in the exploded view. Each such modular piece-part 325 mayinterlock with the adjacent modular piece-part 325 and the twointerlocked piece-parts 325 may then be bolted together. Once theassembled substrate is complete, then the gas flow components 323,which, in this example, are all valves of various types, may beassembled to the assembled substrate. Seals 327 may be interposedbetween the gas flow components 323 and the piece-parts 325 in order toprovide a gas-tight seal interface. The gas flow path through such amodular gas stick assembly is represented by the flow arrows in FIG. 4;it is to be understood that the internal features of the valves in thisexample are not depicted, although such valves may be any of a varietyof surface-mount valve technologies readily available in the industry.

Disclosed herein is a gas delivery substrate for mounting gas supplycomponents of a gas delivery system that may be formed from stackedlayers which are bonded together to create a uniform monolithicstructure that is configured to receive and mount gas supply componentssuch that the gas supply components are in fluidic communication witheach other via channels within the substrate. The layered structure ofthe substrate may allow gas channels or conduits to be created of anysize and in any of several directions. In some implementations, thelayered substrate may also include channels or conduits for runningelectrical wire connections between gas supply components or may includeelectrical conductors that are embedded within the substrate for asimilar purpose. In some alternative of further such implementations,the layered substrate may also include heater elements that are housedin one or more channels routed in a layer of the substrate, e.g., alayer of the layered substrate may have one or more meandering channelsthat each house a resistive heater element. In some alternative orfurther such implementations, the substrate may include channels orconduits for carrying pressurized air between gas supply components. Forexample, the channels or conduits within the substrate may providepneumatic supply connections between a pneumatic manifold and diaphragmvalves, e.g., on/off valves. For example, the diaphragm valves mayinclude a solenoid which is actuated by pressurized air in order tocontrol the flow of gas. Thus, gas supply components may be housedcloser together on the substrate and the connections between componentsmay be made shorter than the connections within substrate 322, as shownin FIG. 3.

FIGS. 7-9 illustrate layers from an example of a layered gas deliverysubstrate for mounting gas supply components of a gas delivery systemfor a semiconductor processing apparatus, as disclosed herein. FIGS. 7-9each show an example of a single layer which may be included in such asubstrate; these layers may be stacked together (including withadditional layers not pictured here) and then bonded together. Thelayers of the substrate may be made from any suitable material, such asceramic, metal, metal alloy, glass, or composites. One or more layers ofthe substrate may also include one or more chambers or plenums, e.g., amixing chamber. In some implementations, the substrate may include oneor more chambers or plenums which extend through two or more layers ofthe substrate to form part of a mixing chamber. In some implementations,the substrate may have one or more flow restrictors, e.g., a filter orfrit with one or more small openings, embedded within one or more of thelayers, e.g., such as within a channel of a layer or housed within athrough-hole of a layer. In addition, a flow splitter, e.g., aT-junction, +-junction, or other multi-path junction, may be createdwithin one or more layers of the substrate for diverting gas.

As shown in FIGS. 7-9, a layer 700 may include multiple verticalthrough-holes 710 and horizontal channels or passages 720. Verticalthrough-holes 710 may be configured as gas conduits to provide fluidiccommunication between channels in different layers, between ports onopposing outer surfaces of the substrate, or between a port on an outersurface of the substrate and a channel or channels in one or more of thelayers (vertical through-holes that connect an internal passage orchannel of the substrate to an exterior surface of the substrate mayalso be referred to herein as “drop-holes”). Mounting holes 708 mayprovide through-holes through which threaded fasteners, e.g., screws orbolts, may be inserted in order to fasten or attach gas supplycomponents to the substrate. The mounting holes 708 may also be blindholes with internal threads or threaded inserts. The verticalthrough-holes 710 used for gas conduits may be coated with one or moreadditional materials, such as metal, glass, plastic, ceramic, metalalloys, or composites. In FIGS. 7-9, the vertical through-holes 710 arethe smaller-diameter holes, and the mounting holes 708 are thelarger-diameter holes, as shown in the “Hole Size Guide” included withFIGS. 7-9.

It is to be understood that, vertical through-holes 710 may take any ofa variety of shapes or follow any of a variety of directions, i.e., theyare not necessarily constrained to be vertical (perpendicular to thesubstrate), but may also be slanted or have other geometries. In somecases, the vertical through-holes 710 of multiple layers may beconfigured so as to line up and create a gas-tight connection that spansmultiple layers when the layers are bonded together. Additionally, somevertical through-holes 710 in a given layer may connect with a channelson the opposite side of the layer, or may connect two channels onopposing sides of the layer. The vertical through-holes 710 also may benon-cylindrical, e.g., they may be tapered, or may change size from onelayer to another, e.g., for a series of three vertical through-holes 710that align with one another in a layer stack, the middle verticalthrough-hole 710 may have a larger diameter, allowing a frit or otherflow restriction device or filter device of that larger diameter to beinserted into the middle vertical through-hole 710, where it may betrapped in place by the smaller-diameter vertical through-holes 710 inthe adjacent layers. In some implementations, vertical through-holes 710may extend vertically or at an angle in any direction within the threedimensional space of a layer (e.g., X-direction, Y-direction, andZ-direction).

Also shown in FIG. 7, a layer of the gas delivery substrate may includehorizontal channels 720, i.e., channels that traverse the layers indirections parallel to the plane of the major surface(s) of the layer.Horizontal channels 720 may be linear, follow curvilinear paths, orsplit into or join with multiple other horizontal channels. Horizontalchannels 720 may extend partially into or completely through a layer.Also, horizontal channels 720 may vary in cross-section as they traversea layer. For example, the horizontal channels 720 may have a depth thatis deeper at one end and shallower at another end, potentially resultingin a decreasing or increasing cross-sectional area perpendicular to thedirection of flow within such a channel. The slope of a channel may alsobe varied (e.g., zigzag, curving or undulating). In addition, horizontalchannels 720 may be configured to create a gas-tight connection withvertical through-holes 710 and/or horizontal channels 720 of anotherlayer when the layers are bonded together to form a gas conduit.Alternatively, vertical through-holes 710 may connect to horizontalchannels 720 within the same layer, e.g., on opposite sides of the samelayer, to form a gas conduit. Horizontal channels 720 may be setparallel to a plane of the layer or at any angle with respect to theplane of the layer. Interior surfaces of horizontal channels 720 andvertical through-holes 710 may be coated with corrosion resistantmaterial, such as siloxane, see U.S. Patent Application Publication No.2011/0259519, the disclosure of which is hereby incorporated byreference in its entirety, which discusses such treatments. In somecases, horizontal channels may partially or fully overlap, when viewedfrom a direction normal to the major surfaces of the layers, otherhorizontal channels in other layers or on an opposite side of the layerhaving such horizontal channels. Also, some horizontal channels maycross over other horizontal channels and/or some vertical channels. Inthis way, connections between gas supply components may be moreefficiently routed, in order to save space and reduce the overallfootprint of the substrate.

As discussed earlier, the horizontal channels 720 may follow any path,e.g., straight, rectilinear, meandering, winding, curved, orcurvilinear, within a layer. For example, horizontal channels 720 mayextend radially from a common point and then follow a curved path, e.g.,to form a radial array of J-shaped paths.

One or more of the layers may also include a larger volume that mayserve as a mixing chamber or manifold. For example, the center “hub”from which the eight spoke channels 720 radiate in the layer shown inFIG. 9, which is indicated with a dotted circle and the reference 712,may serve as a mixing chamber or manifold.

FIGS. 10 and 11 show an example of a gas delivery substrate for mountinggas supply components of a gas delivery system including multiple layersprior to those layers being bonded together. FIGS. 10 and 11 showdifferent layers 700A-700F of a substrate 700; FIG. 10 shows anisometric exploded view from one side, and FIG. 11 shows an isometricexploded view from the other side. The channels 720 are, in thisexample, all located on the surfaces of the layers facing in the samedirection, although in other implementations, some of the channels 720may be located on surfaces of the layers facing in opposite directionsfrom other surfaces of the layers having channels 720. Generallyspeaking, each vertical through-hole 710 and channel 720 in each layermay line up with a corresponding vertical through-hole 710 in at leastone adjacent layer. As shown, the substrate 700 may include as manylayers as are needed in order to achieve the desired routing paths forgas flow streams. For example, the substrate 700 in this exampleincludes six layers 700A-700F, including outer layers 700A and 700F, andinner layers 700B-700E. Each layer of the substrate may have verticalthrough-holes and/or horizontal channels. Also, each layer may includeone or more chambers or plenums, e.g., such as a mixing chamber 712,which may extend partially through a layer or completely through one ormore layers. Depending on the materials used to make the layers of alayered substrate, the layers may be bonded together through firing,sintering, adhesive, friction welding, pressure (such as through hotisostatic pressing), welding, soldering, cold spraying, and heattreatment, ultrasonic welding, cooling, brazing, or diffusion bonding.By selecting a proper material for each layer and the bonding material,the substrate may have improved corrosion resistance and gas puritywhile also reducing cost by avoiding expensive metal alloys, e.g.,Hastelloy®, or stainless steel, e.g., 316. Alternatively, the layers maybe clamped together through any mechanical means, such as clamps, bolts,screws, rivets, or through-bolts.

FIGS. 12 and 13 illustrate the gas delivery substrate layers of FIGS. 10and 11 bonded together to form a monolithic substrate structure 700. Thelayers of the substrate 700 may be made of the same material such that,when bonded together, they form a uniform, monolithic structure(although if a material is used to facilitate the bonding, e.g., anadhesive or braze material, such material may differ from the layermaterial). Each layer of the substrate may have a uniform thickness or anon-uniform thickness. Alternatively, different materials may be usedfor each layer. For example, the outer layers may be formed from ahigher quality material than the inner layers and vice versa. Inaddition, the layers may have identical overall shapes or differentoverall shapes or configurations. For example, two smaller-area layersmay both be bonded to the same side of a common, larger layer. Inanother example, one layer may have a rectangular shape while anotherlayer may have a circular shape.

As can be seen in FIGS. 12 and 13, once the layers are bonded together,the channels 720 within the substrate are sealed off, leaving thevertical through-holes 710 as the only fluidic connection between thosechannels 720 and the fluid flow components that may be mounted to thesubstrate 700 by way of the mounting holes 708.

The substrate may be formed such that it is configured to receive andmount gas supply components on the exposed out major surfaces of thetopmost and/or bottommost layer of the substrate. In addition, thesubstrate may be formed with three sides or more sides (e.g., atriangular shape, a rectangle, pentagon, hexagon, etc.), such that theone or more sides of the substrate are configured to receive and mountgas supply components. Alternatively, the layered substrate may beformed in a circular, oval or curvy shape (e.g., a single verticalside). Also, the substrate may be formed with a mixture of flat angularsides and curved sides (e.g., a “D” shape). In addition, the substratemay be formed such that it is configured with one or more gas inlets andone or more gas outlets. The gas inlets and outlets may be included inany layer or across more than one layer of the substrate. The gasoutlets may be configured to connect to one or more gas lines and/or aprocessing chamber downstream.

FIG. 14 depicts a three-dimensional rendering of the fluid flowconduits, e.g., channels and vertical through-holes, located within thesubstrate 700 of FIGS. 10-13. FIG. 14 does not show the substrateitself, nor show the mounting holes. FIG. 14 may be thought of as adepiction of the structure that would occur if a molten material were tobe flowed through all of the flow conduits within the substrate andallowed to cool and harden into a solid, and the substrate thensubsequently removed without damaging the cooled, solid material. As canbe seen, the conduits are able to follow complicated paths that overlapone another, criss-cross or cross over one another, etc. Moreover,certain portions of these conduits may be identical for each individualgas flow path. For example, each of the eight, straight radial spokechannels that radiate outward from the mixing chamber near the center ofthe conduit network is the same length, and connects up with verticalthrough-holes that may connect up with a different pair on/off valves ofsixteen on/off valves mounted on opposing sides of the substrate. Theseon/off valves may, in turn, each be connected, via another verticalthrough-hole, with one of the sixteen identical J-shaped channels thatare arranged in a radial array around the mixing chamber. Each J-shapedchannel may, in turn, be connected, via another vertical through-hole,with a different one of sixteen mass flow controllers that are mountedon opposing sides of the substrate. The J-shaped channels and straightradial spoke channels, and the vertical through-holes connecting themwith the valves and mass flow controllers, may all be identical (ormirror images of one another) such that transit time and delivery delayof the gas that is metered out from the mass flow controllers is notdependent on the mounting locations of the mass flow controllers or thevalves. Upstream of the mass flow controllers, however, the channels andvertical through-holes may differ in length and configuration/shape fromflow path to flow path. Since these differences, if they exist, areupstream of the mass flow controllers, however, such differences wouldnot cause differences in transit time or delivery delay of the gasesinto the mixing chamber. In FIG. 14, some of the connections betweenchannels/vertical through-holes that are provided by valves or mass flowcontrollers are indicated by dotted lines (with arrows indicatingdirection of flow).

As can be seen in FIG. 14, a plurality of vertical through-holes mayserve as gas inlets 1420; each gas inlet 1420 may have a manual shut-offvalve connected to a process gas interfaced to it and may be fluidicallyconnected to an upstream gas supply channel 1440, which, in turn, may befluidically connected with another vertical through hole located at theopposite end of the channel 1440; this vertical through-hole may beconnected to a mass flow controller, the exit of which may befluidically connected with vertical through-holes 1460, which may be influidic communication with, as shown in the depicted example, theJ-shaped passages. Each J-shaped passage may fluidically connect one ofthe vertical through-holes 1460 with another vertical through-hole thatmay be interfaced with a shut-off valve, which may then connect with oneof the radial channels 1450 leading to a mixing chamber 1430; the mixingchamber 1430 may be fluidically connected by another channel to anoutlet 1470.

In addition to housing conduits within the layers of the substrate, oneor more layers of the substrate may include a gas flow splitter (see,for example, splitter 701 in FIG. 11), a heater, a restrictor (e.g., afilter with one or more small holes), and/or a gas mixing manifold. Inan implementation, the layers of the substrate may include air conduits.For example, the air conduits may allow a pneumatic manifold to connectto and control diaphragm valves or air actuators mounted on thesubstrate.

FIG. 15 depicts a plan view of the example gas delivery substrate ofFIG. 12. As can be seen, the channels, shown in dashed lines, in the gasdelivery substrate may pass over or under one another, follow commonpaths at different elevations at times, and otherwise achieve flowgeometries that are difficult or impossible to achieve usingconventional gas stick implementations.

FIGS. 16 and 17 depict isometric views of an implementation of a gasdelivery substrate as described herein with associated gas supplycomponents of a gas delivery system for a semiconductor processingapparatus. FIG. 16 is an isometric view of a gas delivery substrate 1602that forms a gas delivery system 1600, and FIG. 17 is an isometricexploded view of the substrate 1602. As discussed, the substrate may beconfigured to receive and mount a variety of different gas supplycomponents; a seal 1654 may be sandwiched between each gas supplycomponent and the ceramic substrate 1602 in order to provide aleak-tight seal. In the particular implementation shown, the locationsof many of the gas supply components, e.g., valves 1610 and MFCs 1608,on both sides of the substrate match up so that a single set offasteners 1646 (bolts) and 1650 (nuts) may be used to mount two opposinggas supply components to the substrate—this may be more clearly evidentin the exploded view of FIG. 17. It is to be understood that a varietyof different types surface-mount gas supply or gas flow components (suchas the valves 1610 and MFCs 1608) may be mounted to the gas deliverysubstrate, including, but not limited to, vacuum coupling radiation(VCR) fittings, electronically operated gas valves,pneumatically-operated gas valves, manually-operated gas valves, gaspressure regulators, gas filters, purge gas supply components, gas flowrestrictors, and/or pressure transducers. The gas delivery substrate1602 may receive process gases via a plurality of gas inlets 1612. Forexample, the gas supply components may be organized in differentsections on any side of the substrate. In addition, the substrate may beconfigured with one or more gas outlets or openings for allowing gas toexit the substrate. The outlets may be included on any side of thesubstrate. The gas outlets may be configured to connect to one or moregas lines and/or a processing chamber downstream.

The gas delivery substrate may be configured to receive and mount gassupply components such that different components may be shared betweendifferent gas lines. This design may save space and reduce costs whilealso reducing gas pulsing and switching times. In addition, FIGS. 16 and17 illustrate an example of a substrate that is configured to receiveand mount some gas supply components in a radial or circular arrayarrangement on the substrate. In other words, some of the gas supplycomponents may be arranged in a ring formation around a common point,such as a mixing chamber within the substrate. For example, thesubstrate may include a multi-inlet mixing chamber, similar to themixing chamber 712, where the gas inlets from the MFCs and/or the on/offvalves interposed between the MFCs and the mixing chamber are spacedequally from the center mixing chamber. In such an arrangement, thelength scales for all gas species approach zero, or are zero.

For example, a mixing manifold within the substrate may include acylindrical or spherical mixing chamber defined by features within oneor more layers of the substrate, and the gas inlets may be located atcircumferentially spaced locations on any side of the substrate. Byhaving all of the gas supply flow paths terminate in a radial spokearrangement, as opposed to the traditional “comb” approach whereindividual gas sticks form the “tines” of the comb and the mixingchamber is formed by the “spine” of the comb, a spherical or cylindricalmixing chamber may be used. Moreover, the mixing chamber volume may beconsiderably smaller when compared to a mixing chamber that isfluidically connected with a large number, e.g., 16, gas sticks laid outside-by-side one another, as is traditionally done in gas boxes. Such aradial arrangement allows for both high flow and low flow gases to bemixed effectively instantly, and for co-flow effects, i.e., gas mixingdelays due to gas position or location, to be virtually or completelyeliminated.

In some implementations, a manual valve may be mounted on the gasdelivery substrate for carrying out the supply or isolation of aparticular gas supply. The manual valve may also have a lockout/tagoutdevice above it. Worker safety regulations often mandate that plasmaprocessing manufacturing equipment include accidental activationprevention capability, such as a lockout/tagout mechanism. A lockoutgenerally refers, for example, to a device that uses positive means suchas a lock, either key or combination type, to hold an energy-isolatingdevice in a safe position. A tagout device generally refers, forexample, to any prominent warning device, such as a tag and a means ofattachment that may be securely fastened to an energy-isolating devicein accordance with an established procedure.

A regulator may be mounted on the gas delivery substrate to regulate thegas pressure of the gas supply and a pressure gas may be used to monitorthe pressure of the gas supply. In implementations, the pressure may bepreset and need not be regulated. In other implementations, a pressuretransducer having a display to display the pressure may be used. Thepressure transducer may be positioned next to the regulator. A filtermay be used to remove impurities in the supply gas. A primary shut-offvalve may be used to prevent any corrosive supply gases from remainingin the substrate. The primary shut-off valve may be, for example, atwo-port valve having an automatic pneumatically operated valve assemblythat causes the valve to become deactivated (closed), which in turneffectively stops gas flow within the substrate. Once deactivated, anon-corrosive purge gas, such as nitrogen, may be used to purge one ormore portions within the substrate. The purge gas component and thesubstrate may have, for example, three ports to provide for the purgeprocess (i.e., an entrance port, an exit port, and a discharge port).

A mass flow controller (MFC) may be located adjacent the purge valve.The MFC accurately measures the flow rate of the supply gas. Positioningthe purge valve next to the MFC allows a user to purge any corrosivesupply gases in the MFC. A mixing valve next to the MFC may be used tocontrol the amount of supply gas to be mixed with other supply cases onthe substrate. In an implementation, a portion of the MFC may be builtinto one or more layers of the substrate. For example, a flow restrictor(e.g., a filter with one or more small holes) or a flow diverter may bebuilt into one or more layers of the substrate.

In implementations, a discrete MFC may independently control each gassupply. Example gas component arrangements, and methods and apparatusesfor gas delivery are described, for example, in U.S. Patent ApplicationPublication No. 2010/0326554, U.S. Patent Application Publication No.2011/0005601, U.S. Patent Application Publication No. 2013/0255781, U.S.Patent Application Publication No. 2013/0255782, U.S. Patent ApplicationPublication No. 2013/0255883, U.S. Pat. Nos. 7,234,222, 8,340,827, and8,521,461, each of which are commonly assigned, and the entiredisclosures of which are hereby incorporated by reference herein intheir entireties.

In other implementations, MFCs may be used to initiate the desired flowset point for each gas and then release the respective gases forimmediate mixing in a mixing manifold or chamber within the gas deliverysubstrate. Individual gas flow measurement and control may be performedby each respective MFC. Alternatively, a single MFC controller mayoperate multiple gas lines.

In some implementations, the MFCs that are mounted to the substrate maybe controlled by a remote server or controller. Each of the MFCs may bea wide range MFC having the ability to perform as either a high flow MFCor a low flow MFC. The controller may be configured to control andchange the flow rate of a gas in each of the MFCs.

The present disclosure further provides, in implementations, a method ofusing a gas delivery substrate for mounting gas supply components of agas delivery system for a semiconductor processing apparatus forsupplying process gas to a processing chamber of a plasma processingapparatus. Such a method may include, for example, delivering differentgases between gas supply components mounted on the substrate throughconduits within the substrate to a mixing manifold or chamber within thesubstrate. Initially, the gases are delivered to the substrate through aplurality of gas inlets on a surface of the substrate. After mixingwithin a mixing manifold or chamber, the gases exit the substratethrough one or more outlets. The gas inlets may be equally spaced from acenter mixing chamber of the mixing manifold, such that the length scaleof each gas species is the same and when gas is flowed from gas suppliesto the mixing manifold within the substrate, the gas delivery time foreach gas is the same. Alternatively, the gas supply components and gasinlets may be spaced in linear or non-linear arrangements.

Such a method may further include, for example, delivering gas through agas delivery substrate including a first layer having verticalthrough-holes, a second layer having vertical through-holes andhorizontal gas channels, and a third layer having verticalthrough-holes. The first, second, and the third layers of the substratemay be bonded together such that the horizontal gas channels of thesecond layer may be in fluidic communication with at least some of thevertical through-holes in the first layer and/or the third layer. Themethod further includes delivering the gas between a plurality of gassupply components via the second layer and the first layer and/or thethird layer of the substrate. In addition, the gas delivery substratemay include one or more openings for allowing gas to exit the substrateto one or more gas lines or to a downstream processing chamber.

In addition, the present disclosure provides a method of supplyingprocess gas through a gas delivery substrate for mounting gas supplycomponents to a processing chamber of a plasma processing apparatus.Such a method may include, for example, delivery of gases from aplurality of gas supplies in fluidic communication with a plurality ofgas inlets on a surface of a substrate for mounting gas supplycomponents and having at least one mixing chamber and an outlettherefrom; flowing at least two different gases from the plurality ofgas supplies to the substrate to create a gas mixture in the mixingchamber; and supplying the gas mixture to a plasma processing chamberfluidically coupled with the gas delivery substrate downstream of thesubstrate. In some implementations, the gas mixture may be combined witha tuning gas before delivery to a downstream processing chamber.

In some such implementations, mass flow controllers may initiate flowset points for each of the at least two different gases and release themsimultaneously for immediate mixing in a mixing chamber within thesubstrate. One of the gases may be a tuning gas which may be deliveredto the mixing chamber.

In some implementations, gas may enter the substrate via a plurality ofgas inlets/openings on a surface of the substrate and enter a mixingchamber within the substrate. The gas mixture may then exit thesubstrate via one or more exit outlets/openings from the mixing chamber.After exiting the substrate, the gas may be delivered to one or more gaslines, or directly to a processing chamber. The mixing chamber may beprovided within one or more layers of the substrate or be external tothe substrate. In other implementations, the gas may be added to anotherarray of gases or mixed gases, another substrate mounted with gas supplycomponents, or a gas stick.

It is to be understood that the above monolithic or layered substrateconcepts may allow the components for controlling multiple differentprocess gases of a semiconductor processing tool to be mounted to thesame component, i.e., the monolithic or layered substrate. In previousgas distribution systems for semiconductor processing tools, eachprocess gas was typically handled by a discrete gas stick, i.e., thevalves, mass flow controller(s), etc. for controlling each gas flow weremounted to a separate substrate, which, in some instances, was built upfrom modular substrate elements as shown in FIG. 3. In some typicalarrangements, such separate gas sticks (and their separate substrates)were then arranged in a linear array, with each gas stick teeing into acommon mixing line (as opposed to a much smaller mixing chamber). As aresult, the mixing volume for a conventional gas box was typicallyprovided by a long tube or flow channel that is connected to each gasstick in the linear array—thus, the mixing volume in a conventional gasbox may be a tube or flow passage that is at least as long as the widthof the side-by-side gas sticks, in aggregate. For example, if each gasstick is 1.5″ in width, and there are 16 gas sticks, then the mixingvolume in a conventional system may be a gas passage that is at least24″ in length; if the gas passage is a nominal 0.25″ in diameter alongthis length, then the mixing volume of such a passage is greater than4.7 cubic inches.

In comparison, a monolithic or layered substrate, as disclosed herein,may allow for radial arrays of gas flow components and flow passages,which, in turn, allows for a mixing volume that may be concentrated in amuch smaller area and thus be much smaller in volume, e.g., less than acubic inch. This smaller mixing volume size reduces purge times, as wellas the time needed to effectively mix the gases flowed into the mixingchamber. Another benefit offered by a radial array of gas flowcomponents, as discussed above, is that the final transit distancebetween the mixing chamber and the last fluid flow component for eachprocess gas flow path may be made equal for each process gas, whichmakes the transit times of each process gas to the mixing chamberinsensitive to the radial positioning of the terminal gas flowcomponents for that process gas in the gas flow component array.

It is to be understood that layered substrates, as described herein, mayallow for most or all of the gas flow components downstream of theprimary shut-off valve, i.e., most or all of the gas flow componentstypically included in a gas stick, for most or all of the process gassupply lines for a gas distribution system to be mounted to one commonsubstrate. For example, in a gas distribution system that distributes 16separate gases using a layered substrate component, the gas flowcomponents for 12, 14, or 16 of these gases may be mounted to the samesubstrate.

Special Considerations for Ceramic Substrates

As discussed above, the multi-layered substrate gas distribution systemsdescribed herein may, in some implementations, be made from ceramiclayers that are bonded together or otherwise manufactured such thatexterior surfaces of the substrate are ceramic. However, ceramicmaterials present some unique manufacturing challenges that mayintroduce complexities in the manufacture of such substrates that arenot issues when making such substrates out of more conventionalmaterials, such as machinable metals.

Ceramics are sintered materials, i.e., a powdered ceramic material isshaped into a form of some sort and then heated or “fired” at hightemperature to fuse the ceramic particles into a cohesive solid. In theunfired or “green” state, ceramics are typically low-strength and may bereadily machined. In the fired state, ceramics are much stronger buttypically also more brittle. Moreover, in the firing process, mostceramic materials experience significant shrinkage, e.g., ^(˜)20%. Suchshrinkage may not be uniform, which may introduce additional issues.

The machining of green ceramics may be performed using traditionalmachining techniques, e.g., milling, boring, drilling, etc., or by moreadvanced techniques, such as laser cutting. These techniques may,however, may leave a rough surface finish. For example, in lasercutting, outgassing from the laser cutting process may causefluctuations in the laser beam intensity, width, and focusing, which mayresult in small surface irregularities that result in a rough surfacefinish. The granular nature of the green ceramic may also contribute toincreased surface roughness in a ceramic part, as compared with amachined metal part—even if the ceramic is machined using traditionaltechniques.

Sealing

One issue that arises in using a gas distribution system featuring aceramic substrate is the issue of mounting flow control components, suchas valves, mass flow controllers, etc. having, for example,surface-mount valve interfaces, to the ceramic substrate such that agas-tight seal exists between the flow control components and theceramic substrate. In a traditional gas stick arrangement, metal C-sealsor other crushable, metal seals are typically used for such purposes;the crushable metal seals are interposed between the metal bases of thegas flow components and the metal substrates used in such traditionalgas stick arrangements and then compressed, which deforms the seals andforms a gas-tight seal interface. Thus, the sealing interface in atraditional gas stick arrangement is typically a metal-metal-metalcontact arrangement. Such sealing interfaces are typically provided byproviding a shallow counterbore feature, typically sized based on theouter diameter of the crushable metal seal, on both the gas flowcomponent base and the metal substrate. The discussion herein relatingto sealing surfaces may be applied to seals utilizing a variety ofdifferent crushable metal seals, including C-seals, W-seals, and otherseal types. Although the following discussion and examples featureC-seals, it is to be understood that the seal face preparationtechniques discussed herein also may be applied to seals utilizing othertypes of crushable metal seals.

FIG. 18 depicts an exploded section view of a typical C-seal interfacebetween a gas supply component and a metal base. FIG. 19 depicts asection view of the assembled C-seal interface of FIG. 18. A gas supplycomponent 1858, which may be made of metal, may be bolted to a metalbase 1860; the gas supply component in this example is held in placewith respect to the metal base 1860 by bolts 1846, which are threadedinto nuts 1850. The gas supply component 1858 and the metal base 1860both have counterbore features 1862 that are sized to receive a metalC-seal 1856, which may be snapped into a seal retainer 1854 that mayhold the metal C-seal 1856 in place during assembly and may ensure thatthe metal C-seal 1856 is properly seated before being compressed whenthe gas supply component 1858 is clamped to the metal base 1860.

For gas-tight connections, the surfaces of such counterbore featuresthat seal against the crushable metal seals, e.g., the flat floors ofthe counterbore features, are typically burnished to a surface roughnessof 8-16 pin Ra to provide a gas-tight connection for smaller-moleculegases such as helium, hydrogen, and Freon, or 16-32 pin Ra to provide agas-tight connection for larger-molecule gases such as air, nitrogen,argon, and natural gases. Surface finishes that are smoother than 8 pinRa may actually impair sealing, and are thus not recommended bymanufacturers of crushable metal seals (see, for example, “SurfaceRoughness Recommendations” on page E-80 of the “Metal Seal Design Guide”published by Parker Hannifin Corporation in July 2013).

The present inventors, however, determined that in the context of aceramic/crushable metal seal interface, the ceramic portion of theinterface may actually benefit from having a surface roughness rangethat is outside of the typical recommended surface roughness ranges. Intesting ceramic interfaces to metal C-seals, the present inventorsdiscovered that ceramic surfaces having surface roughnesses in the rangeof surface roughnesses recommended by the C-seal manufacturer did notprovide a sufficiently leak-proof interface according to SEMI F1standards. SEMI is a global industry association for the semiconductormanufacturing industry and publishes a collection of standards governingvarious aspects of semiconductor manufacturing equipment. The F1standard (as of this writing, the F1-0812 standard) is titled“Specification for Leak Integrity of High-Purity Gas Piping Systems andComponents,” and requires a “leak-tight” seal to have an inboard leakrate of less than 10⁻⁹ cm³ atmospheric He/sec. The present inventorsdetermined that the failure of industry-standard metal C-seal interfacesto achieve such leak rates when used to seal against a sintered ceramicsurface was likely due to the fact that sintered ceramic materials areporous, whereas metal sealing surfaces are not. The present inventorsdecided to polish the ceramic surface that seals against the metalC-seal to a surface roughness of 5 μin Ra or better, which is more than30% smoother than the minimum manufacturer-recommended surfaceroughness. The resulting ceramic seal interfaces were tested with bothstandard 316L stainless steel C-seals and harder Hastelloy® C-22C-seals, and each exhibited leak characteristics meeting the SEMI F1standards for over 50 assembly-disassembly cycles (the metal C-sealsused were replaced after each cycle, as such seals are not re-usable).This unexpected result suggests that standard crushable metal seals maybe used with a ceramic sealing surface by polishing or lapping theceramic sealing surface to a surface roughness that is considerablysmoother than the typical manufacturer surface roughness recommendation.

FIG. 20 depicts a flow diagram for a technique for preparing a ceramicsubstrate for interfacing with a gas flow component using a standardcrushable metal seal, such as a metal C-seal. In block 2002, a ceramicsubstrate, or layers thereof, may be machined, e.g., machined in a greenstate, so as to have a number of gas flow channels and holes passingthrough the ceramic substrate that fluidically connect the channels withthe exterior surface(s) of the ceramic substrate. In block 2004, theceramic substrate (or stacked layers thereof) may be fired in a kiln oroven in order to sinter the ceramic material used into a monolithicblock. In block 2006, the surfaces of the ceramic substrate where metalC-seals will be interfaced may be polished to a surface roughness lessthan or equal to 5 μin R_(a). In block 2008, a crushable metal seal maybe located relative to a hole located either in the ceramic substrate orin a gas flow component. In block 2010, the gas flow component may bemounted to the ceramic substrate, e.g., using a bolted connection, andthen clamped in place, sandwiching the crushable metal seal between thepolished or lapped portion of the ceramic substrate and the base of thegas flow component.

In some implementations, the ceramic substrate may, similar toconventional seal interfaces on steel components, have individualcounterbores sized to receive a crushable metal seals, and the “floors”of such counterbores may be individually polished to achieve the 5 μinR_(a) or less surface roughness discussed above. If there are amultitude of such features, as will typically be the case in amultilayer substrate such as those discussed above, this may betime-consuming. An alternative approach is to forego individualcounterbore features on the substrate, and instead simply polish or lapthe entire surface(s) on which the gas flow components are to be mountedto the desired 5 μin R_(a) or less surface roughness. A separatetemplate or templates, such as templates 1614 in FIG. 17, which may bemade of metal, ceramic, or other material, that is sized with athickness that is similar to the depth of a “typical” counterborefeature used to receive a metal seal may be laid on top of the mountingsurface(s) and interposed between the gas flow components and thesubstrate. The template may have holes in locations corresponding to theholes in the ceramic substrate; these holes may be sized slightly largerthan the outer diameter of the metal seals, and may serve to locate themetal seals relative to the holes in the ceramic substrate to which thegas flow components are being sealed. If this technique, which isdescribed in more detail in U.S. patent application Ser. No. 14/843,775,filed on Sep. 2, 2015, which is hereby incorporated by reference in itsentirety, is used, then the desired surface roughness for all of theseal interfaces on a common side of the ceramic substrate may beachieved using a single polishing or lapping operation on the entireside surface.

FIG. 21 depicts a cross-section of an arrangement in which the entiresurface of a ceramic substrate may be polished or lapped to a surfaceroughness of less than or equal to 5 μin R_(a). As can be seen, theupper surface of a ceramic substrate 2102 may be flat, allowing for theentire upper surface of the ceramic substrate 2102 to be polished orlapped at once to a surface roughness of less than or equal to 5 μinR_(a). After this surface roughness is achieved, a component-locatingtemplate 2114 may be placed on the ceramic substrate 2102 and lined upwith a gas flow port 2164 on the ceramic substrate, such as the gas flowport depicted. Such alignment may be achieved by lining up a referencefeature or features on the template with corresponding referencefeatures, such as a pin 2122, in the ceramic substrate 2102—this mayallow the template to be aligned with multiple gas flow portssimultaneously. After the component-locating template 2114 is placed onthe ceramic substrate, a metal C-seal 2156 may be installed in acounterbore formed by a hole 2130 in the component-locating template2114 that is of a larger diameter than the gas flow port in the ceramicsubstrate 2102 upon which the hole is centered. A seal-locating template2154 may assist with placement of the metal C-seal 2156. Once the metalC-seal 2156 is installed, a gas flow component 2158 having a counterbore2162 around a port 2165 may be located on the metal C-seal and installedusing bolts 2146 and nuts 2150, for example.

Particulate Control

Another issue that arises in the use of ceramic substrates in the gasdistribution context is that of particulate contamination. As discussedearlier, sintered ceramics have high porosity, which may cause the raw,machined surface finishes of sintered ceramic components to exhibitincreased surface roughness as compared with a machined metal substrate.Moreover, if a technique such as laser cutting is used to shape thechannels in a multi-layer ceramic substrate, the resulting sidewallroughness of the channels (the side walls of the channels are generallyparallel to the laser beam path) may be considerably rougher due tofluctuations in the laser beam intensity and/or width as a result ofoutgassing. Laser cutting is a fast and cost-effective technique thatmay be used to create the two-dimensional layers that may be used in themanufacture of a layered ceramic substrate. In testing performed by thepresent inventors, gas channel sidewall surface roughness arising fromlaser cutting of the channels was measured to be on the order of 185 to255 μin S_(a) (area-based average roughness), as compared with surfaceroughnesses of 20 to 28 μin S_(a) for the bottoms or tops of suchchannels, which were provided by the surfaces of adjacent layers in thelayered ceramic substrate and which were not laser cut.

The high surface roughness of the channel sidewalls presents a problemin that surfaces of such a high surface roughness are more likely to a)trap and retain particulates and b) more likely to be sources ofparticulates themselves, e.g., if a ceramic particle that contributes tothe high surface roughness breaks off from the surface. For example, intesting, it was determined that the particulate purging time for aceramic substrate was more than twice as long as the particulate purgingtime for an equivalent stainless steel gas distribution manifold(although the stainless steel manifold was made with stainless steeltubing rather than as a layered substrate). In particulate purging timetests, a purge gas is flowed through the gas flow system being testedand the time it takes until any particles that may be in the exiting gasflow are less than a certain size is evaluated. In the testing that wasdone, the time it took until only particles of less than 100 nm in sizeexited the substrate was used to determine the particle purging time.

The present inventors determined that subjecting a sintered ceramicsubstrate for use in a gas distribution system to a coating process maybe an effective way to improve the surface finish within the channelsand reduce or prevent particulate contamination. The coating may servetwo purposes: a) to trap any existing particles, e.g., ceramic particlesthat may not have effectively fused with neighboring ceramic particlesduring the sintering process, and b) to fill in the gaps and crevicesthat may exist between sintered ceramic particles, thereby reducing theavailable surface area on which particulates from elsewhere in the gassystem may temporarily get caught or snagged.

Several different types of coatings may be used for such purposes,including glaze coatings, chemical vapor deposition (CVD) coatings, andatomic layer deposition (ALD) coatings, as well as other coating typesthat may provide the functionality discussed above.

In glaze coatings, a silica- or alumina-containing material may beapplied to the exposed surfaces of a ceramic part and the ceramic partmay then be exposed to high heat in a kiln or other oven, melting thesilica-containing material. When the melted silica glaze re-cools, itwill, due to being in a molten liquid state, have flowed into the gapsand crevices of the ceramic part, and will form a more rounded, smootherprofile when it solidifies. Particulates that may have been lodged inthe crevices and gaps of the ceramic part may be cemented in place bythis coating. Glazes may be applied through any of a variety oftechniques, including by dry-dusting the channels and other surfaces ofinterest with the glaze material prior to insertion into a kiln,inserting glaze materials in the kiln or oven such that the glazematerial migrates into the kiln atmosphere and thus transfers to thepart to be glazed, or by suspending the glaze materials in an aqueoussuspension, flowing the suspension through the channels, and then firingthe ceramic component in the kiln.

In CVD coating operations, the ceramic substrate may be placed in a CVDchamber and exposed to a chemical vapor deposition environment thatdeposits a polymer coating, such as a Parylene™ coating, or othergenerally non-reactive coating, such as, for example, a silicon oralumina coating, on surfaces of the ceramic substrate. In suchoperations, it may be beneficial to draw a vacuum on the passages of theceramic substrate during the coating operation to draw the CVD gasesinto the channels to ensure that the CVD coating is applied to thechannels within the interior of the ceramic substrate. For example, ifthe ceramic substrate is supported by a pedestal within the CVD chamber,the pedestal may have one or more vacuum ports that may correspond inlocation with locations in the exterior surface of the ceramic substratewith ports leading the channels within the ceramic substrate. Duringprocessing operations, vacuum drawn on these ports may draw CVD gasesinto the channels, ensuring that they are coated with the CVD coating.

Polymer coatings, while very compatible with CVD processes, are somewhatfragile, and may be easily damaged. For example, if a polymer coatingfrom a channel extends along the interior surfaces of a through-holeconnecting that channel to an exterior surface of the ceramic substrate,and then extends to the exterior surface of the ceramic substrate, thepolymer coating may, when a gas flow component that is mounted to thatexterior surface of the ceramic substrate is removed for maintenance,stick to the gas flow component (or the metal seal that seals the gasflow component to the ceramic substrate) and pull away from thesidewalls of the through-hole when the gas flow component is removed.Each time the gas flow component is removed, there may be a potentialfor further damage to the coating, and gas flow components may need tobe removed many times during the lifetime of the gas distributionsystem.

To avoid such potential issues with a CVD coating, the majority of thesurfaces of the ceramic substrate to which gas flow components may bemounted may be kept free of the coating through appropriate masking.FIGS. 23 through 25 depict simplified cross-sectional views of a ceramicsubstrate and masking components during various stages of a CVD coatingapplication. For example, in FIG. 23, a plate or template 2462 may beplaced against a ceramic substrate 2360. The plate or template 2362 mayhave through-holes 2364 in it corresponding to the locations of eachdrop-hole or through-hole on an exterior surface of the ceramicsubstrate and may be placed over the ceramic substrate 2360 such thatthe through-holes 2364 on the plate or template line up with thecorresponding drop-holes or through-holes in the ceramic substrate 2360.The plate or template 2362 may, for example, be made of any suitablematerial, e.g., alumina, stainless steel, etc., and may includecounterbores for locating seals 2366 that seal against the ceramicsubstrate 2360 at each drop-hole or through-hole location. When theplate or template 2362 is placed against the ceramic substrate 2360,these seals 2366 may be interposed between these two components at eachdrop-hole or through-hole location. In CVD operations, which typicallyoccur at temperatures of several hundred degrees, metal seals may beused due to the high heat. The template or plate may then be fixed inspace relative to the ceramic substrate, e.g., by bolting the two piecestogether. Thus, when CVD process gases are flowed into the CVD processchamber, such as in FIG. 24, and into the passages within the ceramicsubstrate 2360, the exterior surface of the ceramic substrate to whichthe template or plate is mounted may be “masked” off by the template orplate, thereby preventing CVD of the coating 2368 on the ceramicsubstrate 2360 in the masked locations. When CVD processing is complete,then the template or plate 2362 may be removed, as shown in FIG. 25.During removal, the CVD coating 2368, which may have formed a generallyconformal coating along the inside surfaces of the flow paths thatbridge between the ceramic substrate 2360, the metal seals 2366, and thetemplate or plate 2362, may break, tear, or otherwise experience anuncontrolled termination event at the ceramic substrate 2360/seal 2366interface. However, for future assembly/disassembly operations of gasflow components to the ceramic substrate, there will be minimal or nocontact between the terminated ends 2370 of the coating(s) and the metalseals that may be used to mount such gas flow components to the ceramicsubstrate, which may reduce the risk of further damage to the coatings.

In typical ALD coating operations, a first reactant may be flowed into areactant chamber, usually followed by a purge cycle, and then a secondreactant may be flowed into the reactant chamber. The reactantstypically react with the exposed surfaces of whatever component is inthe chamber in a self-limiting way to produce a single-molecule thicklayer. By keeping the first reactant and the second reactant flowsseparate, each reactant flow may only react with the single-moleculethick layer of the previous reactant on the component that is exposed tothe chamber atmosphere. As a result, ALD coatings are 100% conformal,but must be manufactured one molecular layer at a time; this may requirehundreds (or thousands) of repetitions of the first and second reactantdeposition cycles to achieve a desired thickness, which means that ALDcoating operations are typically far more time-consuming than CVDcoating operations. Due to the conformal nature of ALD films, however,they form highly durable coatings. ALD may also be used to form nitride,alumina, or other ceramic coatings, allowing for the ceramic substratechannels to be coated in the same material that may be used to form theceramic substrate.

The thickness of the layers formed on the surfaces of the gas flowchannels within a ceramic substrate may be selected such that the layerthickness is either greater than the surface roughness, e.g., for asurface roughness of 250 μin S_(a), the thickness may be 250 μin orgreater, or greater than the smallest particle size used in themanufacture of the ceramic substrate, e.g., if 100 nm diameter ceramicparticles were sintered to form the ceramic substrate, then the coatingmay be at least 100 nm thick. Such coatings may “glue” potentially looseparticles in place, and may also fill in crevices and gaps that mayotherwise act to trap additional particulates. In some instances, it maynot be econominally feasible to achieve such layer thicknesses, e.g., ifALD is used to provide the coating, the cost of performing sufficientALD cycles to achieve the desired coating thickness may be prohibitive.In such cases, a thinner surface coating may be used, although such athinner surface coating may exhibit poorer particulate performance.

FIG. 22 depicts a flow diagram for a technique for preparing a ceramicsubstrate for a semiconductor tool gas distribution system so as to havea reduced likelihood of particulate contamination. In block 2202, aceramic substrate for a gas distribution system of a semiconductorprocessing tool may be manufactured. Such manufacture, for example, mayby way of techniques discussed herein, or by other techniques notdiscussed herein. The ceramic substrate resulting from block 2202 maygenerally be “complete,” in the sense that it has already been sinteredand, in most cases, machined, if necessary. In block 2204, the ceramicsubstrate may be coated with a corrosion-resistant coating to a desireddepth, e.g., at least as large as the smallest, nominal size of ceramicparticles used in the manufacture of the ceramic substrate or to a depthequivalent to the maximum surface roughness of the walls of the interiorflow channels or passages of the ceramic substrate.

The coating operations of block 2204 may be provided by any suitabletechnique, including the three specific techniques shown. For example,if glazing is used, a silica-containing glaze may be added in block 2206to the gas flow channels and other interior passages within the ceramicsubstrate, e.g., through flowing aqueous glaze through the flowchannels, applying dry glaze materials to the flow channels, or,alternatively, applying the glaze in the subsequent block viasalt-firing the ceramic substrate.

In block 2208, the glazed ceramic substrate may be fired in a kiln oroven to a temperature above the melting point of the glaze, but belowthe melting point of the ceramic substrate. The glaze may then melt andfuse with the ceramic substrate; once the glaze has been melted, theceramic substrate may be removed from the kiln or oven and cooled,leaving a durable, chemically-resistant surface coating on the walls ofthe gas flow channels and other interior flow passages of the ceramicsubstrate that cements existing particles in place and provides lesspotential for trapping new particles that may be flowed into the ceramicsubstrate during use.

If a CVD process is used to provide the coating instead, then theceramic substrate may optionally be prepared in block 2210 by maskingoff portions of the internal passages that are near the exteriorsurfaces of the ceramic substrate on which gas flow components may bemounted. For example, for each vertical through-hole that reaches theexterior surface of the ceramic substrate, a millimeter or so of thatvertical through-hole that is closest to the exterior surface of theceramic substrate may be masked off to avoid depositing the CVDmaterial, e.g., a polymer, on that portion of the vertical through-hole.This may avoid potential damage to the CVD coating caused byinteractions with other components that are mounted to the ceramicsubstrate.

In block 2212, the ceramic substrate may be placed into a CVD chamber.In some implementations, the ceramic substrate may be one of severalceramic substrates that are placed into the same CVD chamber and coatedsimultaneously (batch-coating ceramic substrates may also be done ifglazing or ALD coatings are pursued).

In block 2214, the ceramic substrate may be subjected to a CVD processin which a polymeric coating is deposited on the surfaces of the gasflow passages within the ceramic substrate. In some implementations, theentire ceramic substrate (except for the areas that may be potentiallymasked) may be subjected to the CVD operation. The CVD process may beperformed for a duration of sufficient length that the desired thicknessof coating within the interior passages of the ceramic substrate isobtained.

If an ALD process is used to provide the coating, then the ceramicsubstrate may be placed in an ALD process chamber in block 2216,potentially with additional ceramic substrates that may be coatedsimultaneously. After the ceramic substrate is placed in the ALD processchamber in block 2216, the ceramic substrate may be subjected to aplurality of ALD cycles in block 2218 until the coating on the surfacesof the internal passages of the ceramic substrate have reached thedesired thickness.

It is to be understood that for ALD-applied coatings, a similar maskingtechnique may be used as in CVD coatings, although re-usable rubbero-ring seals may be used in place of metal seals since ALD processes areoften performed at much lower temperatures. While most ALD coatings maynot be at risk of damage from mounting or dismounting gas flowcomponents, it may be preferable nonetheless to institute a form ofmasking, similar to that described above with respect to CVD, and toconfine the ALD process gases such that only a subset of the surfaces ofthe ceramic substrate, e.g., the interior passage surfaces, are coatedwith an ALD coating. This may avoid subjecting the entire ceramicsubstrate to repeated ALD cycles, which may decrease the amount of timeneeded to purge each ALD process gas prior to initiating the next ALDcycle. For example, if the ALD process gases are confined so as to onlyflow into the internal passages of the ceramic substrate, it maygenerally only be necessary to purge those same passages, as comparedwith, for example, the larger process chamber volume. This may greatlydecrease the time needed to form a coating of a desired thickness.

While implementations disclosed herein have been described in detailwith reference to specific implementations thereof, it will be apparentto those skilled in the art that various changes and modifications maybe made, and equivalents employed, without departing from the scope ofthe appended claims.

1. A gas delivery system for a semiconductor processing apparatus, thegas delivery system comprising: a substrate including: a plurality oflayers having major surfaces thereof bonded together forming a laminate,wherein the major surfaces of each layer are on opposite sides of thelayer, the major surfaces of the layers that are bonded together areinterior major surfaces of the laminate, and the major surfaces of thelayers that are not bonded to another of the layers are outer majorsurfaces of the laminate; a mixing chamber extending from a firstinterior major surface of the interior major surfaces into the layerhaving the first interior major surface; a plurality of radial spokechannels extending from the first interior major surface into the layerhaving the first interior major surface, radiating outward from themixing chamber, and having the same length; a plurality of firstsurface-mount valve interfaces, wherein each first surface-mount valveinterface is located on one of the outer major surfaces, includes acorresponding first through-hole through one or more of the layers, acorresponding second through-hole through one or more of the layers, acorresponding plurality of first mounting holes, and is fluidicallyconnected within the laminate to a corresponding one of the radial spokechannels via the corresponding first through-hole; a plurality of secondsurface-mount valve interfaces, wherein each second surface-mount valveinterface is located on one of the outer major surfaces and includes acorresponding third through-hole through one or more of the layers, acorresponding fourth through-hole through one or more of the layers, anda corresponding plurality of second mounting holes; a plurality of firstgas channels, each first gas channel extending at least partially intoone of the interior major surfaces; a plurality of second gas channels,each second gas channel extending at least partially into one of theinterior major surfaces; a plurality of first gas conduits, each firstgas conduit including one of the first gas channels and fluidicallyconnecting one of the second through-holes with one of the thirdthrough-holes within the laminate; and a plurality of second gasconduits, each second gas conduit including one of the second gaschannels and fluidically connected with one of the fourth through-holeswithin the laminate, wherein: each first surface-mount valve interfaceis configured to interface with a corresponding first gas flow componentvia the first mounting holes of that first surface-mount valveinterface, and each second surface-mount valve interface is configuredto interface with a corresponding second gas flow component via thesecond mounting holes of that second surface-mount valve interface. 2.The gas delivery system of claim 1, wherein the radial spoke channelsare arranged in a circular array around the mixing chamber.
 3. The gasdelivery system of claim 1, wherein at least one of the layers includesone or more items selected from the group consisting of: one or moreheaters for heating gas, a gas flow splitter, a filter forming a gasrestrictor, and a non-linear gas channel.
 4. The gas delivery system ofclaim 1, wherein the substrate includes at least one gas channel orthrough-holes that forms an oblique angle with respect to a plane of alayer.
 5. The gas delivery system of claim 2, wherein there are eightradial spoke channels.
 6. The gas delivery system of claim 1, whereinthe mixing chamber extends into more than one of the layers.
 7. The gasdelivery system of claim 2, wherein the radial spoke channels areequally spaced around the mixing chamber.
 8. The gas delivery system ofclaim 1, wherein the layers are bonded through a process selected fromthe group consisting of: firing, sintering, adhesive, welding,soldering, cold spraying and heat treatment, ultrasonic welding,brazing, and diffusion bonding.
 9. The gas delivery system of claim 1,wherein each layer is made from a material selected from the groupconsisting of: ceramics, glass, metals, and polymers.
 10. The gasdelivery system of claim 1, wherein the layers having outer majorsurfaces include a plurality of gas inlets and one or more gas outlets.11. The gas delivery system of claim 1, wherein the laminate includesone or more items selected from the group consisting of: a) air conduitsextending through one or more of the layers and configured to carry airbetween a pneumatic manifold and diaphragm valves and b) wire conduitsextending through one or more layers and configured route wires to orfrom gas supply components.
 12. The gas delivery system of claim 1,further comprising a plurality of gas flow components mounted on atleast one of the outer major surfaces, wherein: the plurality of gasflow components includes the plurality of first gas flow components andthe plurality of second gas flow components, and the gas flow componentsare selected from the group consisting of: an on/off gas valve, a massflow controller (MFC), a vacuum coupling radiation (VCR) fitting, amanual gas valve, a gas pressure regulator, a gas filter, a purge gascomponent, a gas flow restrictor, and a pressure transducer.
 13. The gasdelivery system of claim 12, wherein the plurality of gas flowcomponents are mounted on opposing outer major surfaces of thesubstrate.
 14. The gas delivery system of claim 12, wherein: the firstgas flow components are on/off gas valves, the second gas flowcomponents are MFCs, and each on/off gas valve is fluidically connectedto a corresponding one of the MFCs via a corresponding one of the firstgas conduits.
 15. The gas delivery system of claim 14, wherein: (a) someof the gas conduits crisscross each other and at least some of themounted gas flow components are arranged on one or two outer majorsurfaces in a non-linear arrangement, or (b) some of the gas conduitscrisscross each other, and at least some of the mounted gas flowcomponents are arranged on one or two outer major surfaces in a circulararrangement.
 16. The gas delivery system of claim 14, wherein gas flowpaths between gas inlets on the laminate to the mixing chamber in thelaminate have equal lengths.